PM-355 Nuclear Track Detector Research Articles

Carbon nanotubes embedded in a polyimide foil for proton acceleration with a sub-ns laser

A series of thin films made of aligned carbon nanotubes (CNTs) embedded in a polyimide substrate was designed, fabricated and used for the first time to accelerate protons and C ions by interaction with a sub-nanosecond, high power laser beam (600 J energy and 300 ps pulse width) with peak intensity of about 3 × 1016 W/cm2 on target. Each target was 5 µm thick, and the composite material contained CNTs aligned in different directions in the substrate. The results obtained from the analysis of a Thomson Parabola spectrometer, and of the spots imprinted by ions on a series of PM355 nuclear track detectors, indicate high energies (up to 3 MeV for protons and 9 MeV for C ions) and a marked influence of the CNTs’ orientation on the produced proton beam current. An increase of the proton fluxes, more than two orders of magnitude, was recorded with the targets containing CNTs aligned parallel to the target normal, in comparison to the other targets. The presented experimental results demonstrate that the laser-driven proton beam flux can be increased using ad hoc designed targets (with embedded and aligned nanotubes) and sub-nanosecond laser pulses with moderate intensities and poor temporal contrast, thus in an acceleration regime very far from those typically investigated experimentally using relativistic intensities (>5 × 1018 W/cm2) and short laser pulses (10 fs to 10 ps).

Estimation of radioactivity in plankton deposited on air conditioner filters in the old area of Mosul city, Iraq

ABSTRACT The essential objective of this study was to estimate 222Rn, 238U, and 226Ra concentrations of plankton samples, along with the risk indices defined by PAEC, Ep, AED and CPPP. These analyzes were carried out on plankton samples from fifteen-alley air conditioner filters in the old Mosul area. In this analysis, using the cumulative monitoring technique of the PM-355 nuclear track detector. The maximum concentrations of radon, uranium, radium and risk indices were observed in Bableksh (sample 5) alley at 77.77(Bq. m−3), 3.74(ppm), 21.46(Bq.kg−1), 0.0084(mWL), 0.3465(WLMY−1), 1.962(mSv.y−1), and 35.31(per 106person). Whereas at Al Hadhira alley the minimum was found to be 39.07(Bq.m−3), 2.05(ppm), (10.78 Bq.kg−1), 0.00422(mWL), 0.1741(WLMY−1), 0.9856 (mSv.y−1), and 17.74(per106 person. The average concentrations of radon, uranium, radium and, risk indices of all studied alleys were 59.156 ± 10.7 (Bq. m−3), 2.803(ppm) ± 0.48, 16.34 ± 4.49(Bq.kg−1), 0.00646((mWL)) ± 0.00011 , 0.2662 (WLMY−1)± 0.0517 , 1.506 (mSv.y−1)± 0.279 , and 27.116 (per 106person)± 5.043 , respectively. Alpha indexes were estimated for all surveyed alleys, in addition to the radioactivity tests and the risk indices. Their values varied between 0.053 and 0.107, with an average 0.081 ± 0.0021. Such levels are significantly smaller than the total dose given by the United Nations Scientific Committee on the effects of atomic radiation, especially at Exposure to 222Rn progeny (Ep) which is within the range of 0.2–10 mSv.y−1 (UNSCEAR). Appropriate correlations between radon concentration with uranium and radium concentration (R2 = 0.8739 and 0.896) have been identified, respectively. The results revealed that the amount of background radioactivity of the alleys of old Mosul area would be within acceptable limits.

Effect of Solar radiation induced and alpha particles on Nonlinear behavior of PM-355 film

In the current work of radiology, polymeric sheets of the PM-355 nuclear track detectors (SSNTDs) were exposed with α-particles and solar radiation for several exposure times. The absorption spectrum of samples exposed to the sun showed that the edge of the absorption accidentally changed to longer wavelengths. An investigation of continue waveguide laser effects on the nonlinear absorption properties of nuclear track polymer has been done. Non-linear absorption increases with increasing levels of exposure to sunlight and is highly connected to revealed surface morphology and chemical structural modifications. In case of high solar radiation flux and α-particles irradiation, the nuclear track detectors showed high nonlinearities, represented by the appearance of a number of diffraction rings.

Photoluminescence characterizations and nonlinear optical of PM-355 nuclear track detector film by alpha-particles and laser irradiation

The imaging processing technique was used for studying a laser beam nature that transmitted through films of PM-355. The thermal nonlinearity of PM-355 films was studied using a 635 nm cw diode laser at 15 mW as the source of excitation. Third order nonlinear optical properties of PM-355 films irradiated with α-particles at different times and pristine sample has been studied using Z-scan technique. The samples showed a negative and large nonlinear refractive index and reverse saturable absorption (RSA) with high values of the nonlinear absorption coefficient. The fluorescence spectra of PM-355 films were investigated at room temperature and wavelength range of 250–500 nm for a pristine film and in different times of exposure to α-particles. The broad peaks were between 350, 420 and 465 nm. All-optical switching property of PM-355 samples irradiated with α-particles at 20 min was also studied using the standard pump-probe technique.

Changes induced in structure and optical properties of PM-355 nuclear track detector due to laser irradiation

ABSTRACTPM-355 is a class of polymeric solid-state nuclear track detectors which has a lot of applications in several radiation detection fields. Samples from sheets of PM-355 have been exposed to infrared (IR) laser fluences ranging from 1 to 12.8 J/cm2. The effect of IR laser radiation on the structural properties of PM-355 has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the samples exhibit chain scission under the effect of laser irradiation up to 4.2 J/cm2, thus producing free radicals that led to the formation of new bonds started and continued until 12.8 J/cm2. This reduces the ordering structure, giving the PM-355 polymer more resilience. In addition, the laser irradiation at the fluence range 4.2–12.8 J/cm2 led to a more compact structure of PM-355, which resulted in an improvement in its isotropic nature with an increase in Vickers hardness and refractive index. Further, the color changes due to laser irradiation were computed using the transmission data in the wavelength range of 370–780 nm. It is found that the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the laser fluence, largely depending on the proportions of the blue color component.

Optical limiting behavior correlated with the surface and etching time of irradiated nuclear track detector

The effects of different laser incident intensity on the optical characteristics of PM-355 nuclear track detector have been studied by using photoluminescence (PL) and UV–visible spectroscopic techniques. The polymers were irradiated with alpha particles with close contact to 241Am (in contact with a mean energy 5.49 MeV) and then exposed to continues waveguide (cw) laser with different incident intensity. A noticeable decrease in the photoluminescence spectral intensity was observed with increasing laser incident intensity. From the UV–visible spectra, it is found that a shift in the absorption edge towards a longer wavelength with increasing laser incident intensity can be readily observed. The absorption peak with increasing incident intensity is seen to change into a broad one. The optical band gaps determined from the UV–visible spectra were found to decrease with the increase of cw laser doses. The calculations were made of the number of carbon atoms per conjugation length, N and number of carbon atoms per clusters, M embedded in the network of polymers. The effective of etching time on optical power limiting behavior of sample was also investigated. The optical power limiting behavior was found to vary with the etching time. It also shows a very good optical limiting behavior with a limiting threshold varying from 16.6 to 19.9 mW. These results indicate that the PM-355 nuclear track detector is a promising candidate for applications in the nonlinear optic field.

Structural and optical investigation of the effect of electron beam irradiation in a PM-355 nuclear track detector

The effect of electron beam irradiation on the structure and optical properties of a PM-355 solid-state nuclear track detector has been investigated. Samples from PM-355 were irradiated with electron beams with different doses ranging from 20 to 250 kGy. The structural and optical modifications in the electron beam-irradiated PM-355 samples have been studied as a function of dose using different characterization techniques such as Fourier transform infrared spectroscopy, Vickers hardness, refractive index and color difference measurements. The Commission International de E'Claire (CIE units x, y and z) methodology was used in this work for the description of colored samples. In addition, the color differences between the non-irradiated sample and those irradiated with different electron beam doses were calculated. The results indicate that the PM-355 detector acquires color changes under electron beam irradiation.

Color changes in gamma- and electron-beam-irradiated PM-355 nuclear track detector

The effects of gamma and electron beam irradiation on the color changes of PM-355 nuclear track detector have been investigated. Samples from PM-355 were classified into two main groups. The first group was irradiated with gamma in the dose range of 10–250 kGy, while the second group was irradiated with an electron beam at the same dose range. The transmission of these samples in the wavelength range of 370–770 nm, as well as any color changes, was studied. The Commission International de E'Claire (CIE units x, y and z) methodology was used in this work for the description of colored samples. In addition, the color differences between the non-irradiated sample and those irradiated with different gamma or electron beam doses were calculated. The results indicate that PM-355 detector acquires color changes under gamma and electron beam irradiation, but it has a more response to color changes by electron beam than that by gamma.

Calibration of PM-355 nuclear track detector: For C-ions within the energy range 70–90 MeV

This paper presents investigations of the PM-355 detector, mainly track diameters and depths as a function of C-ion energies and etching time. Using a scanning electron microscopy technique (SEM), we have studied the etch pit depth of tracks produced by C-ions in the PM-355 material. The V B values were estimated by weighing as a function of etching time. The V T values were calculated from the measured length of the etched tracks using Dorschel's relation.

Calibration of PM-355 nuclear track detectors for low-energy deuterons

A dependence of track diameters on deuteron energy was investigated for PM-355 nuclear track detectors. Deuteron streams were obtained from RPI-IBIS facility at the pulsed injection of deuterium. Mass and energy analysis was performed with a Thomson-type spectrometer and PM-355 samples. An etched deuteron parabola extended from about 20 keV to about 500 keV. The energy resolution of measurements on the parabola at 20 keV was ± 0.2 keV , and at 500 keV amounted to ± 50 keV . Accuracy of the determination of deuteron energies decreased for higher energy values. Results are presented in diagrams showing the track diameters as a function of deuteron energy for chosen etching times (1–8 h).

Fast neutron irradiation effects in PM-355 nuclear track detector

Samples from sheets of the polymeric material PM-355 have been exposed to neutrons of incident energy in the range 0.8–19.2 MeV. The resultant effect of neutron irradiation on the thermal properties of PM-355 has been investigated using thermo-gravimetric analysis (TGA). The onset temperature of decomposition T o and thermal activation energy of decomposition E a were calculated, results indicating that the PM-355 detector decomposes in two weight loss stages. The variation of transition temperatures with neutron energy has been determined using differential thermal analysis (DTA). The results indicate the PM-355 thermograms to be characterized by the appearance of an endothermic peak due to melting. Melting temperature was found to be dependent on the neutron energy. In addition, structural property studies using X-ray diffraction and infrared spectroscopy were performed on both non-irradiated PM-355 samples and all of the samples that were irradiated. The results indicate that both the degree of ordering and the absorbance of the PM-355 polymer are dependent on neutron energy.

Corpuscular diagnostics of deuterium-plasma streams from RPI-IBIS discharges

The paper reports on experimental studies of pulsed plasma-ion streams generated by the RPI-IBIS facility equipped with coaxial multi-rod electrodes and operated at about 30 kV, with the pulsed injection of pure deuterium. Ion measurements were performed at time-delays τ (between the gas-valve triggering and a HV pulse) equal to 170 µs (slow mode) and 130 µs (medium mode). To determine mass-and energy-spectra of ions the use was made of a Thomson-type spectrometer. An influence of the initial gas conditions (determined by τ) on the energy spectra of deuterium-ions was demonstrated. To study the spatial structure of plasma-ion streams the use was made of an ion-pinhole camera equipped with PM-355 nuclear-track detectors and placed on the discharge axis. The application of Al-filters enabled to record deuterons of highest energy and to identify sources of their emission. The measurements confirmed the strong influence of the initial gas conditions on the energy distribution of the emitted plasma-ion streams and their spatial structure. The obtained results are of importance for basic plasma physics and for application-oriented research, e.g. modifications of different materials.

Study of spatial structure and energy spectrum of ion beams by means of LR 115A and PM-355 nuclear track detectors

The paper reports on measurements of pulsed plasma-ion streams, as performed with the selected solid-state nuclear track detectors (SSNTD). The ion-beams were produced by an experimental device (RPI-IBIS) equipped with coaxial electrodes (each made of molybdenum rods) and a fast-acting gas valve. The device was operated at 30 kV/44 kJ, with puffing of pure hydrogen or deuterium. The spatial structure of the ion beams was studied with pinhole cameras equipped with replaceable detectors, and ion mass- and energy-spectra were measured with a Thomson spectrometer. To analyse low-energy ions (below the energy thresholds of LR 115A and PM-355 SSNTD) an additional accelerating system was applied. It was observed that ions of energy > 30 keV are emitted in bunches, and the ion flux amounts to 2 × 10 12 ions / cm 2 at a distance of 30 cm from the electrodes outlet. Energy spectra of protons and deuterons ranged from about 30 keV to about 400 keV. The ion distributions, as recorded by means of the PM-355 and LR 115A detectors, are similar.

Calibration of PM-355 nuclear track detectors; comparison of track diameter diagrams with track depth characteristics

The calibration diagrams, i.e. track diameters and track depths versus ion energy and etching time, as obtained for PM-355 track detector irradiated with He-ions are presented. The both detector characteristics are compared. The track etch rate is determined by two methods, as a function of the etch pit depth and the ion energy loss.

Imaging of Fusion Protons from a 3 kJ Deuterium Plasma Focus

This paper reports a study of the proton emission from a 3 kJ, 14 kV plasma focus device operated with deuterium gas at 400 Pa. A filtered pinhole camera with a 1.8 mm diameter hole is placed axially downstream of the plasma focus, and images of the proton-emitting region are recorded using CR-39/PM-355 nuclear track detectors. The detector plates are scanned using an automated track measurement system and the spatial track density profile is acquired. The resulting density distribution is interpreted with the help of a simple pinhole imaging model that assumes the 2H(d, p)3H reaction protons are emitted from a conical region extending from the tip of the anode to a fixed distance downstream. Comparison of the experimental track density profile with the model calculations supports the view that the beam-target mechanism is the dominant fusion production mechanism in this small plasma focus device.

Determination of radon exhalation rates from tiles using active and passive techniques

Measurements of radon exhalation rates for selected samples of tiles used in Saudi Arabia were carried out using active and passive measuring techniques. These samples were granite, marble and ceramic. In the active method, a PC-based radon gas analyzer with emanation container was used, while, in the passive method, PM-355 nuclear track detectors with the “can technique” were applied for 180 days. A comparison of the exhalation rates measured by the two techniques showed a good linear correlation coefficient of 0.7. The granite samples showed an average radon exhalation rate of 0.7 Bq m −2 h −1 , which was higher than that of marble and ceramic by more than twofold. The radon exhalation rates measured by the “can technique” showed a non-uniform exhalation from the surface of the same tile.

Advantage of PM-355 nuclear track detector in light-ion registration and high-temperature plasma diagnostics

Detailed calibration studies of selected types of SSNTDs have been performed at the SINS using monoenergetic light ions of energy within MeV range. These studies were motivated by the application of such detectors in the optimal way for plasma physics experiments. This paper shows track diameter evolutions versus particle energy and etching time. Some conclusions related to track registration phenomenon and detection properties of the investigated detectors, especially of the PM-355 type are also presented.